Recent Noteworthy Studies to Stimulate Discussion and Debate
■ Women and AMD. Two articles in the April 2011 issue of Archives of Ophthalmology address issues of lifestyle and diet relative to early AMD prevention and prognosis in women. The first article, the latest publication from the CAREDS (Carotenoids in Age-Related Eye Disease Study) team, sought a correlation between responses on a food frequency questionnaire and future AMD diagnosis. The study used the modified 2005 Healthy Eating Index (HEI-2005) and combined those scores with a physical activity measurement to produce a Healthy Lifestyle Score, which they compared with AMD rates.
Women in the highest quintile (best diets) on the HEI-2005 had 46% lower odds of being diagnosed with early AMD than women in the lowest quintile, and women with higher levels of physical activity 4% lower odds of early AMD than women in the lowest quintile for exercise. Most importantly, those women whose behaviors consisted of a combined healthy diet, high level of physical activity, and not smoking had 71% lower odds for AMD.
The second article, also from the CAREDS team, looked specifically at vitamin D's relationship with early AMD by seeking correlations between serum vitamin D levels and AMD status and adjusting for other factors, such as smoking, diabetes and hormone therapy use. The CAREDS team found that vitamin D levels were associated with lower odds of early AMD in women younger than 75 years old but higher odds in women ≥75. For women <75, their positive correlation was bolstered by oral vitamin D dosing. Here, the CAREDS team urges more study of vitamin D's relation to AMD.
■ RPE replacement therapy. A review article in the April 2011 issue of the British Journal of Ophthalmology summarizes the evidence available for successful replacement of the retinal pigment epithelium. Scientists in London and Oxford write that, while suspensions of autologous RPE cells from the peripheral retina have been under investigation for several years, the need for any RPE replacement for AMD to also replace Bruch's membrane has complicated the search for a suitable source for RPE replacement therapy.
However, in the same issue of the BJO, another UK team, this one from Southampton, reports that a copolymer compound, combined specifically in a 25:75 ratio, was able to maintain a transplanted human RPE cell line for four weeks in vitro. These authors conclude that this new copolymer blend may ultimately serve as a scaffold by which autologous RPE cells may be transplanted into an AMD-affected RPE in order to regenerate both RPE and Bruch's membrane cells.
Together, the articles demonstrate the distance that stem-cell therapies have come in retina. Although human applications will take more time, thanks in particular to the discovered ability to generate stem cells without requiring a donated oocyte, those therapies may arrive sooner rather than later.
■ PDT in combination. A team of retinal physicians in Beirut have collaborated on a study comparing ranibizumab monotherapy to ranibizumab in combination with a single session of verteporfin/PDT in wet AMD. They report their findings in the April 2011 issue of Retina.
The study team enrolled 40 eyes with wet AMD from 30 patients and allocated them to the two cohorts. Patients in the monotherapy group received three monthly injections, while the combination therapy group also received PDT one hour prior to a single ranibizumab injection, although retreatment was available as needed to both cohorts.
At 12 months, the monotherapy group experienced a mean gain of 12 ETDRS letters, while the combination therapy group had a gain of only 3.2 letters, although neither group showed significant deterioration of VA or lack of anatomical improvement as determined using OCT. The monotherapy group required more frequent retreatment.
This study will complement the SUMMIT trials data investigating similar combination therapies, although those trials did offer retreatment with PDT. The authors state in closing that there still appears to be an important role for PDT in AMD treatment.
■ Avastin in CRVO. Graefe's Archive of Clinical and Experimental Ophthalmology published in its April 2011 issue the results of a small trial of bevacizumab in serous macular detachment resulting from central RVO. Doctors collaborating between Germany and Turkey retrospectively reviewed 19 cases in which bevacizumab was used.
At a mean follow-up of 21.6 months, 15 of the 19 eyes were nonischemic on examination. Furthermore, BCVA improved from 20/317 at baseline to 20/160, and central foveal thickness decreased from 918 ±280 µm to 432 ±281 µm. Sixteen patients had complete resolution of their serous macular detachment. The authors of the study also provide a case report from their series of patients.
While the authors concede that the study's retrospective and noncontrolled nature limit the applicability of its findings, they nevertheless state that their data add to the growing number of studies indicating a role for bevacizumab in complications of RVO. They urge more work looking specifically at anti-VEGF agents in serous macular detachment due to RVO. RP